Timeshared BASIC/2000, F

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HP 20854A

Timeshared BASIC/2000, Level F

system operator's manual

HEWLETTi,

^PACKARD

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Preface

This manual is a system operator's guide to Hewlett-Packard 20854A Timeshared BASICj2000, Level F (hereafter called the TSB system). The TSB system can be used to control programming activity in a variety of HP 2000 Computer Systems.

This manual has four sections and several appendices. Section I introduces the TSB system.

Section II defines the TSB system hardware and software environment. Section III describes all system operator interfaces with the TSB system. Section IV details the operating procedures a system operator must follow to ope!ate the TSB system effectively. The appendices include information about the TSB system error messages, disc and drum errors, storing TSB system shut- down tapes, formatting new discs, a cold-dump routine, user terminal characteristics, and TSB system recovery after a power failure. A glossary of terms and an index conclude the manual.

This manual presumes that the system operator knows how to operate the equipment in his TSB system environment. Programming considerations for the TSB system are beyond the scope of this manual; they are described in the 20854A Timeshared BASICj2000, Level F reference manual, part number 02000-90073.

While this manual is designed to support the operation of this TSB system, it can be used as an operator's guide to several, earlier, versions of Hewlett-Packard Timeshared systems. The following table lists the TSB system operating procedures which are equivalent to the earlier TSB systems.

If the TSB system is:

20854A 20854A-001 20854A-002 20854A-003 20854A-004

Then the operating procedures and capabil ities in this manual are equivalent to these TSB systems:

2000F (options 200 and 500) _r>··... /... ..•... ...••.. ... •...•.... ::.><·.·.·.· ...• ·•·•·•· •••. ... . . . . /

i... ..

•..•.•..•....•

: ... .

I i > . i i · · · i . } / } ..•...•...••• . •...••.•.• ···.·.·.··••···•·•··· •. X·.·:··

2000F (options 205 and 505)

2000F (options 210 and 510) 2000C (High-speed option)*

2000F (options 215 and 515) 2000C (High-speed option)*

2000F (1600 BPI tape)

*The instructions in this manual presume that the main processor in a system is a 21MX, 2100A or 2100S. Therefore, 2000C (High-speed option) systems which have a 2116B/C as a main processor have some procedures different from those described in this manual.

Order the obsolete manual, part number 02000-90017, from the Hewlett-Packard Customer Service Center for these instructions.

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Preface

SECTION I General Infonnation INTRODUCTION

MASS STORAGE DEVICES Magnetic Tape Unit Moving-head Disc Storage

Fixed-head Drum Storage (options 002 and 003 only) OPERATOR'S CONSOLE

PAPER TAPE READER

MULTIPLEXERS AND DATA SET CONTROL LINE PRINTER

USER TERMINALS Data Transfer Rates Modem Restrictions

SECTION II TSB System Environment SOFTW ARE REQUIREMENTS

MINIMUM HARDWARE REQUIREMENTS Main Computer

I/O Processor

Required Peripheral Equipment Optional Peripheral Equipment HARDWARECONflGURATION

Main Co mputer 110 Processor

1-2 1-2 1-2 1-2 1-2 1-2 1-3 1-3 1-3

1-4 1-4

2-1

2-2

2-3

2-3 2-4

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SECTION III Operator Interfaces With The System SYSTEM ORGANIZATION

COMMUNICATIONS SYSTEM SHUT-DOWN USERS

USER ORGANIZATION Privileged Users Semiprivileged Users Nonprivileged Users LIBRARY ORGANIZATION

Users Private Library

Group Master and Group Library System Master and System Library THE SYSTEM OPERATOR

System Halts

Operator Commands Operator Messages CONSOLE OPERATION

HP 2754A/B Switch Settings HP 2762A Switch Settings System Log

Command Entry

COMMAND DESCRIPTIONS

Command Description Conventions ANNOUNCE

BESTOW BREAK CHANGE COpy

DESECRATE (options 002 and 003 only) DIRECTORY

DISC

DRUM (options 002 and 003 only) DUMP

HIBERNATE KILLID LOAD

LOCK (options 002 and 003 only) MAGTAPE

MLOCK

3-1 3-1 3-1 3-1 3-2 3-3 3-3 3-3 3-3 3-3 3-5 3-5 3-5 3-6 3-6 3-6 3-6 3-7 3-7 3-7 3-7 3-8 3-9 3-9 3-10 3-11 3-12 3-12 3-13 3-14 3-15 3-17 3-18 3-19 3-19 3-20 3-21 3-21 3-22 3-23

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MUNLOCK NEWID PHONES PORT PRINTER PROTECT PURGE REPORT RESET ROSTER

SANCTIFY (options 002 and 003 only) SDIRECTORY (options 002 and 003 only) SLEEP

SPEED STATUS

UNLOCK (options 002 and 003 only) UNPROTECT

SECTION IV Operating Procedures I/O PROCESSOR PROGRAMS

Preparing to Load the I/O Processor Programs Loading the I/O Processor Programs

LOADING THE TSB LOADER LOADING THE SYSTEM PROGRAM INITIAL SYSTEM GENERATION SYSTEM UPDATE

DAIL Y PROCEDURES

Start-up From Disc (base system and option 001 only) Start-up From Disc and Drum (options 002 and 003 only) Start-up From Disc with Paper Tape Loader

Configuration Options Start-up From Magnetic Tape

SYSTEM AND FEATURE LEVEL CODES System Level Codes

Feature Level Code

MASS STORAGE ERRORS DURING START-UP

3-24 3-25 3-27 3-27 3-28 3-29 3-29 3-30 3-31 3-32 3-34 3-35 3-35 3-37 3-38 3-45 3-46

4-1 4-1 4-1 4-2 4-4 4-5 4-5 4-8 4-11 4-12 4-14 4-15 4-19 4-22 4-28 4-28 4-29 4-30

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Disc and Drum Error Conditions (options 002 and 003 only)

Magnetic Tape Error and Loading Messages

APPENDIX A System Halt Codes and Error Messages APPENDIX B Disc and/or Drum Errors

APPENDIX C Storing System Shut-down Tapes APPENDIX D Formatting New Discs

APPENDIX E Cold Dump Routine

APPENDIX F User Terminal Characteristics APPENDIX G Recovery After Power Failure Glossary

Index

FIGURES

Figure 1-1. TSB System

Figure 3-1. TSB System User Classification

4-31 4-32

A-I B-1

C-l D-l E-l F-l G-l Glossary-l Index-l

1-1 3-4

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SECTION I

General Information

INTRODUCTION

The TSB system must consist of a system (main) computer and a communications (I/O) processor to provide support for mass storage devices, an operator's console, a paper tape reader, mUltiplexers, an optional line printer, and the TSB system software.

Figure 1-1 shows the logical organization of the TSB system.

Operator's Console

r - - - ,

I

I I

I

^Line Printer (Optional) I

r--1

_I

I

Terminal I L ______ J

I I

- I

Magnetic

Main Tape Unit

· _· ·

^Processor^I/O ^Computer

Up to 32

Fixed-head User Terminals

or Data Sets Processor Drum Storage

·

Interconnect (options 002

• and 003 only)

· · _·

Terminal

Paper Tape Reader

-

:

Moving-head

I Disc Storage

-

Multiplexers

Power

I Supplies

I I

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MASS STORAGE DEVICES Magnetic Tape Unit

One HP 7970 magnetic tape unit is required by the TSB system. The magnetic tape unit is used for system shut-down and for subsequent system start-up. In addition, it may be used to selectively load or dump programs or files during system loading.

Moving-head Disc Storage

One disc storage device is required to operate the TSB system. The system can support up to eight disc devices. Disc storage can be either HP 7900 devices or HP 2883 devices. Up to four HP 7900 disc devices are supported by one controller interface. Up to two HP 2883 disc devices are supported by one controller interface.

Fixed-head Drum Storage (options 002 and 003 only)

If option 002 or 003 is selected, at least one logical drum storage device is required to operate the TSB system. Up to four logical devices can be supported by the system. Under options 002 and 003, the system drum (logical Drum-a) is assumed present. Additional drums (logical Drum-l through Drum-3) can be added to and removed from the system via the DRUM command (see Section 3).

The HP 2766 is the physical storage device supported by these options. One controller interface is required for each HP 2766 device connected to the system.

Drum storage is not supported or permitted with the base system or option 001.

OPERATOR'S CONSOLE

The operator communicates with the TSB system through an HP 2754A/B teleprinter (all versions), or an HP 2762A Terminal Printer (base system and option 001 only). Using one of these consoles, the operator generates or updates the TSB system, controls and monitors user access to the system, configures ports to a variety of data transmission rates, modifies or examines disc usage directories, changes the hardware configuration on-line, and checks user port activity. In addition, the operator can systematically shut down the TSB system through the console.

PAPER TAPE READER

An HP 2748 paper tape reader is used for entering the loader, I/O processor, and system programs from paper tape into the TSB system during initial generation and subsequent updates to the system.

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MULTIPLEXERS AND DATA SET CONTROL

Each multiplexer installed in the channel slots of the I/O processor (two maximum, see Hardware Configuration, Section II) supports up to 16 user ports for terminals that are connected directly

to

the processor (hardwired). In addition, a data set control interface is associated with each multiplexer. The data set control interface allows terminal connection to the TSB system through telephone data sets. Any combination of data sets and hardwired terminals may be connected and operated concurrently.

If connection is through a data set, the TSB system allows the user 120 seconds within which to log on after telephone connection to the computer is established. If the user does not log on within this time limit, an automatic disconnect occurs. The TSB system operator may use the PHONES command to change the limit.

LINE PRINTER

Optionally, a line printer may be obtained as peripheral equipment for the TSB system. One line printer may be logically connected to (and subsequently disconnected from) the TSB system by the operator using the PRINTER command. The line printer may be one of the following models:

• HP 2610A Line Printer

• HP 2767 A Line Printer

USER TERMINALS

Eight types of user terminals, of which seven are ASCII code generating terminals, can be connected

to

the TSB system. (The IBM 2741 Communication Terminal generates non-ASCII code.) Except for the Hewlett-Packard terminals, the capability to interface with the TSB system is based on the terminal manufacturer's current specifications. If these specifications change in future models, the interfacing capability may be lost.

At system generation, the user ports are configured to a system default data transfer rate. It is the operator's responsibility to reconfigure the user ports to the appropriate data transfer rates using the SPEED command. The following user terminals are supported by the TSB system.

• General Electric TermiNet 1200

• HP 2600A Keyboard-Display Terminal

• HP 2749A/B Teleprinter Terminal

• General Electric TermiNet 300 Data Communications Terminal, Model

B

(10/15/30 cps transfer rates) with Paper Tape Reader/Punch, Option 02

Note: This terminal must be strapped for "ECHO-PLEX",

• Memorex 1240 Communications Terminal (10/15/30 cps transfer rates)

Note: This terminal must be equipped with the even parity checking

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• Execuport 300 Data Communications Transceiver Terminal

• ASR-37 Teleprinter Terminal with Paper Tape Reader/Punch

Note: If this terminal is equipped with the Shift Out (SO) feature, SO must be disabled because the TSB system does not permit use of this feature.

• IBM 2741 Communication Terminal

Note: This terminal should be connected to the computer over telephone lines. In addition, it must be equipped with the following features:

1. Interrupt, Receive (IBM #4708) and Transmit (IBM #7900) associated with the terminal's ATTN key.

2. Dial-up (IBM #3255) to enable system connection through a 103A type modem or acoustic coupler.

Terminals equipped with the automatic linefeed feature (user selectable) must be operated with this feature OFF.

Additional terminal characteristics are given in Appendix F.

Note: Although cursor, form feed, horizontal and vertical tabu- lation, and various special function keys are provided on specific types of user terminals, these capabilities are not supported by the TSB system.

Data Transfer Rates

The TSB system provides for symmetrical rates of data transfer between user terminals and the I/O processor. The operator can use the SPEED command to configure ports for a specific data transfer rate required by the chardcteristics of a user termiRal.

Modem Restrictions

Any 103 type modem that operates in full duplex mode supports data transmission up to the rated speed of the modem and telephone line. Normally, the maximum speed is 300 baud but can be higher.

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SECTION II TSB System Environment

SOFTWARE REQUIREMENTS

The T8B system software is ordered either as a base system, 20854A, or one of four possible options:

20854A-001, -002, -003, or -004. The environment of the T8B system determines which option is ordered, as shown in the following table:

If the TSB Then the environment may include the following devices:

system you as mass storage as operator's console

order is: HP 7900 HP 2883 HP 2766 HP 2754A/B HP 2762A

20854A Yes No No Yes Yes

20854A·001 No Yes No Yes Yes

20854A-002 Yes No Yes Yes No

20854A-003 No Yes Yes Yes No

20854A-004 (substitutes 1600 bpi tape for 20854A 800 bpi tape)

In this manual, references to the T8B system include all options, as well as the base system. However, the portions of this manual which pertain only to certain options are marked accordingly.

MINIMUM HARDWARE REQUIREMENTS

Main Com pu ter

The main computer for the T8B system is an HP 21MX, 21008 or 2100A computer. The main computer must be equipped with the following options:

HP 21MX

• 32K Memory

• Disc ROM Bootstrap Loader

• Dual Channel Port Controller

• Time Base Generator HP 21008

• 32KMemory

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lIP 2100A

• 32KMemory

• Direct Memory Access (DMA)

• Time Base Generator

• Floating Point Hardware

I/O

Processor

The T8B system I/O processor may be an HP 21MX, 21008, 2100A, 2.114B, or 2116B/C computer.

The computer must be equipped with the following options:

UP 2100S

• Processor Interconnect Kit

• One Asynchronous Channel Multiplexer for each set of 16 user terminals supported (two multiplexers maximum)

HP 2100A, HP 21MX

• 8K Memory

• Time Base Generator

• One Asynchronous Channel Multiplexer for each set of 16 user terminals supported (two multiplexers maximum)

HP 2114B or HP 2116B/C

• 8K Memory

• Power Fail/ Auto Restart

• Memory Parity Check

• One Asynchronous Channel Multiplexer for each set of 16 user terminals supported

In addition, the HP 2114B requires an I/O Extender to support more than 16 user terminals (to a maximum of 32).

Required Peripheral Equipment

The following peripheral equipment is required to support the TSB system:

• Paper Tape reader

• Operator's Console

• Magnetic Tape Unit

• Up to 32 User Terminals

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Optional Peripheral Equipment

One line printer can be added to the TSB system.

Note: If this option is selected, a line printer interface board is required (See Hardware Configuration).

Up to seven additional moving-head (disc) storage devices can be added to the TSB system (additional controllers may be required, see Mass Storage Devices - - Section I).

One additional Asynchronous Channel Multiplexer and associated Data Set Control Interface can be added to the TSB system (each multiplexer/data set control interface supports 16 users terminals).

Up to three additional logical fixed-head (drum) storage devices can be added to the TSB system (options 002 and 003 only).

HARDWARE CONFIGURATION

Main Computer

Hardware I/O channel assignments depend on the TSB system option selected. The assignments are as follows:

Base System and Option 001

I/O channel 10-11

8

128 138

14₈ 15-16₈

17-20₈

Contents Processor Interconnect

System Operator's Console Device Controller Photoreader Device Controller

Time Base Generator

First Moving-head Disc Device Controller - - up to four HP 7900 disc devices (base system) or up to two HP 2883 disc devices (option 001) can be associated with this controller

Magnetic Tape Device Controller

Notes: 1) Additional disc device controllers can be assigned to any pair of I/O channels up to 26-27₈provided no previous I/O channels are left empty. It is recommended that any additional disc device controllers be assigned consecutive I/O channel pairs adjacent to the first disc device con- troller channels.

2) The magnetic tape device controller can be assigned to any free I/O channels with preceding empty channels permitted.

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Options 002 and 003

I/O Processor

I/O Channel 10-118

128 13₈

14-158

21-22₈

Contents Processor Interconnect

System Operator's Console Device Controller Photoreader Device Controller

First Fixed-head Drum Device Controller - -

one drum device can be associated with this controller Time Base Generator

First Moving-head Disc Device Controller - - up to four HP 7900 disc devices (option 002) or up to two HP 2883 disc devices (option 003) can be associated with this controller

Magnetic Tape Device Controller

Notes: 1) Additional disC! device controllers can be assigned to any pair of I/O channels up to 26-27₈provided no previous

I/O channels are left empty. It is recommended that any additional disc device controllers be assigned consecutive I/O channel pairs adjacent to the first disc device con- troller channels.

2) The magnetic tape device controller and additional drum device controllers can be assigned to any free I/O channels with preceding empty channels permitted.

The I/O processor configuration depends on the number of user terminals supported, as follows:

1 to 16 Terminals

I/O channel Contents

Processor Interconnect Time Base Generator Multiplexer

Data Set Control Interface Line Printer (optional)

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17 to 32 Terminals

I/O channel Contents

Processor Interconnect Time Base Generator

First Multiplexer

Data Set Control Interface for First Multiplexer Second Multiplexer

Data Set Control Interface for Second Mu Itiplexer Line Printer (optional)

Note: The line printer can be assigned any I/O channel from 16₈to 248 inclusive.

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SECTION III

Operator Interfaces with the System

SYSTEM ORGANIZATION

The TSB system software supervises the operation of the main computer, I/O processor, operator's console, mass storage devices, photoreader, and the multiplexers. In normal operating mode, the system does not require operator supervision. After the operator has brought the system to its normal operating condition, the system recognizes properly identified users, acknowledges legitimate requests, and permits controlled user access to three levels of mass storage libraries. Messages

showing user logging activity are printed and/or punched at the operator's console.

COMMUNICATIONS

The main communications channel -- that between the TSB system and the user -- is described in the reference manual for 20854A Timeshared BASIC/2000, Level F, part number 02000-90073.

Communication between the system operator and the users is confined to messages sent by the operator to all ports during system shut-down (SLEEP and HIBERNATE commands) or by the ANNOUNCE command which may be directed to a specific port or to all ports at any time. A user command, MESSAGE, permits users to send messages to the operator.

Communication between the system and the operator is extensive during start-up, consisting largely of a dialogue initiated by the system requesting specific information from the operator.

During normal operation the operator may request reports from the system or request on-line changes to the system status; otherwise, the only communication from the system are the reports of user logging activity, error halts and messages, and messages from users.

SYSTEM SHUT-DOWN

The operator must use either the HIBERNATE or SLEEP command (this section) to shut down the TSB system in an orderly manner. This permits subsequent quick start-up of the system with no loss of data. Either command causes the entire system (except for the bootstraps) to be written

to disc storage. '

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Under execution of the HIBERNATE command, the contents of the disc are dumped to magnetic tape. Verification of the transferred data is performed if desired by the operator. (Data verification ensures the integrity of the system back-up.) Additional reels of magnetic tape are requested until the disc is dumped completely.

The SLEEP command permits, but does not require, use of magnetic tape. If a dump to magnetic tape is selected, only system information and those user programs and files that have been created or changed since the last successful hibernate operation are transferred. Although back-up sleep tapes are optional, their consistent use substantially improves system reliability. If hardware problems make it impossible to regenerate the TSB system from disc, the operator can use the latest sleep tape and the latest hibernate tape to recover to the point in time that the last sleep tape was written.

For added reliability, additional copies of either hibernate or sleep tapes can be produced immediately following the completion of the original shut-down operation (see HIBERNATE and SLEEP command descriptions). It is recommended that several "generations" of both hibernate and sleep tapes be kept for additional back-up in case the latest tapes are physically damaged or cannot be read. Appendix C contains some suggestions for organizing the storage of shut-down tapes.

Two types of shut-down procedures are provided because of the storage capacity of the TSB system.

In a system with very large user libraries, hibernation of all of the libraries is time consuming and requires many reels of tape. If most of the libraries are used simply for storage and are not changed frequently (the elements in the libraries are referenced but seldom altered), a sleep tape of the same system could be accomplished quickly on a comparatively small amount of magnetic tape. In a small system, or in a system in which most of the user library is modified frequently, there is little difference in either time or tape quantity used which shut-down command is used. In this case, the HIBERNATE command is recommended.

Frequency of shut-down depends on the application of the system. Where the TSB system is shut down daily and the hardware used for other purposes, the HIBERNATE or SLEEP command must be used daily. On a dedicated system that runs around the clock, some down-time should be scheduled for a sleep operation (preferably once a day) and a hibernate operation (weekly) to protect user's data.

The TSB system must be hibernated at least once every six months for proper date verification.

USERS

To log on to the TSB system, each user must enter an identification code, a password, and depending on the user terminal, a terminal-type parameter. The identification code is a single alphabetic

character followed by three decimal digits, AOOO through Z999. The password may consist of as many as six characters (some or all may be non-printing characters for privacy). Both the identification code and the password are assigned to the user by the system operator (see NEWID and CHANGE commands in this section). The terminal-type parameter is a single digit defined by system requirements and described along with the user command, HELLO, in the TSB system reference manual. The identification code and password are not associated with a specific terminal or port, and the same user code can be in active use on a number of terminals simultane-

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USER ORGANIZATION

The users are classified by group according to identification code. Each group is comprised of 100 user codes. For example, AOOO through A099 is a group, AlOO through A199 is another group, and so on through the last possible group, Z900 through Z999. The first identification code within each group is assigned to a user designated as Group Master. The identification code AOOO has special status - - it is assigned to a user designated as System Master. The library associated with identlfication code Z999 can be used to store a program named HELLO which is executed at each user's port at log on time (Z999 is a nonprivileged user identification).

In addition, the users are classified as privileged, semiprivileged, and nonprivileged.

Privileged Users

Privileged users have powers not available to the normal TSB user. They have responsibilities for maintaining the common libraries. The System Master (AOOO) and all Group Masters are privileged users.

Semiprivileged Users

Users with identification codes beginning with the character A, specifically AOOO through A999, are semiprivileged users. When semiprivileged users with the same identification code are logged on at more than one terminal, they can alter their files simultaneously. N onprivileged users can only read files simultaneously. Note that some semiprivileged users are also privileged users (AOOO, A100, ' . " A900).

Nonprivileged Users

All users assigned identification codes greater than A999 who are not Group Masters are nonprivileged users. For example, BOOI through B099, BIOI through B199, and so forth.

Figure 3-1 is a diagram of user classifications.

LIBRARY ORGANIZATION

Each user has access to three levels of libraries - - his own private library, a group library, and the system library.

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USER SEMI- NON-

IDENTIFICATION SYSTEM GROUP PRIVILEGED PRIVILEGED PRIVILEGED

CODE MASTER MASTER USER USER USER

AOOO J J J J

AOOl J GROUP

#1

A099 J

A100 J J J

A10l J GROUP

#2

A199 J

J

BODO J J

BOOl J ^GROUP

#11

B099 J

B100 J J

B101 J GROUP

#12

B199 J

COOO J J

COOl J ^GROUP

#21

C099 J

Cl00 J J

Cl01 ^J ^GROUP

#22

C199 J

ZOOO J J

ZOOl J GROUP

#251

Z099 J

Z900 ^J J

Z901 ^J GROUP

#260

Z999 J

Figure 3-1. TSB System User Classification

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Users Private Library

A private library can be created and maintained by each identification code/password combination.

This library is completely under control of the user assigned that code and password. The user can enter, modify and delete programs and files within his private library.

Group Master and Group Library

The library associated with each Group Master identification code is a common library accessible only to members of the group. The Group Master is responsible for creating and maintaining elements (programs and files) within his Gro~p Library. He can enter, modify, and delete elements in the library in the same manner that normal users do with their private libraries-. However, the Group Master has use of two special commands not available to normal users ~ - PROTECT and UNPROTECT. The PROTECT command adds restrictions to the use of specific elements in the Group Library. A protected program can be executed (RUN) by any member of the group; it cannot be referenced in a SAVE, CSA VE, PUNCH, XPUNCH, or LIST command. A protected file cannot_ be accessed in any manner by members of the group. The UNPROTECT command removes the restrictions from specified library elements. Unprotected elements are generally available to all members of a specific group.

Files within the Group Library can be "mask protected" to insure security of data within the file.

This is accomplished through use of the BASIC language ASSIGN statement. The mask protected status remains with the file until it is removed from the library with a KILL command. A file with mask protected status can be accessed only by the Group Master or by a protected program which has not been modified.

Users other than the Group Master may not modify an element within the Group Library or write it back into the Group Library.

System Master and System Library

The TSB system has exactly one System Master identification code - - AOOO. The basic functions of the System Master are similar to those of the Group Master, but more extensive.

The System Master exercises complete control over the System Library which is available to all other users. He can enter, modify, and delete elements in the System Library and has use of the PROTECT and UNPROTECT commands.

Files within the System Library can be "mask protected" to insure security of data within the file.

This is accomplished through use of the BASIC language ASSIGN statement. The mask protected status rerrlains with the file until it is removed from the library with a KILL command. A file with mask protected status can be accessed only by the System Master or by a protected program which has not been modified.

In addition to being able to protect or unprotect elements in the System Library, the System Master

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only) SDIRECTORY. The System Master has no access to the system through the operator's console, but must gain access through one of the user terminals. If the system operator also acts as System Master, a user terminal independent of the operator's console must be available to the operator.

Although the system operator may also act as System Master, the functions and responsibilities of the two jobs are distinct. The operator controls the system, but has little control over the System Library other than allocating storage and purging the library of inactive elements. The System Master has extensive control of the System Library, but no control over the operation of the system.

Note: Anyone with the proper password can use identification code AOOO and modify the System Library; using control charac- ters (non-printing) in this password can help maintain security.

THE SYSTEM OPERATOR

Although the TSB system is designed to operate with minimum attendance, the system operator is responsible for loading and initiating the system, and for periodic start-up and shut-down of the system.

System Halts

TSB system halts may occur; see Appendix A for a description of those halts and possible corrective action.

Operator Commands

The TSB system provides a group of commands that are accepted through the operator's console device. Included are commands to assign and delete user identification codes, to add or remove user access to peripheral storage or communication devices, to manipulate the elements contained in system and user libraries, to generate reports, to perform system shut-down, and so forth.

Operator Messages

The system provides two types of messages to the operator - - standard operating messages and error messages.

STANDARD OPERATING MESSAGES. The standard operating messages make requests for operator input or action and provide current system activity information to the operator. The operating messages are presented with the operating procedures in Section IV.

ERROR MESSAGES. The error messages inform the operator of errors that occur during system activity. These messages may be printed during system start-up or loading as well as during system

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CONSOLE OPERATION

The system operator's console (sometimes called the system console) can be an HP 2754A/B Tele- printer (available with all options), or an HP 2762A Terminal Printer (available with the base system and option 001 only). When the TSB system is loaded, certain switches on these consoles must be set.

HP 2754A/B Switch Settings

The Status Switch must be set to ON LINE.

The Mode Switch must be set to either:

KT to print all system messages at the console and punch LOGON and LOGOFF messages on paper tape (this is the normal setting)

K to p~int all system messages at the console, but not punch any messages on paper tape T to print all system messages at the console and punch all messages on paper tape.

HP 2762A Switch Settings

The Auto Linefeed Switch must be set to OFF.

The All Caps Switch must be set to ON.

The On Line Switch must be set on (lighted) for the computer to communicate with the console.

Both the On Line and the Ready switches must be on for the operator to communicate with the computer through the console.

The channel type switch must be set to FULL (for full-duplex operation).

The Rate Switch should be set to 30 cps (for efficient operation).

System Log

Note: If switch register bit zero

of

the system (main) computer is set on (lighted), all input from the console (except for a break request) is ignored by the TSB system.

Note: The operator should be familiar with the 2762A escape sequences and control codes. Refer to Operator's Manual 2762A Terminal Printer (part number 02762-90011).

A log, indicating user logging activity, is normally printed and punched at the operator's console.

Each LOGON and LOGOFF message includes user identification code, current time, and port number.

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Command Entry

Upon entry of any system command, only the first three characters of each command are significant;

the remaining characters are superfluous and need not be included. For example, the STATUS command may be entered in any of the following forms:

STA STAT STATU STATUS

If the command requires or permits parameters, a hyphen must separate the command from the parameter string. For example:

PURGE-186/73

If more than one parameter is required or permitted, a comma must separate the parameters. For example:

DISC-l,21,2

Blanks imbedded in the command string are ignored, except within messages specified in SLEEP, HIBERNATE, and ANNOUNCE commands.

Each command string entered must be terminated with a carriage return. If the system cannot interpret an entered command, three question marks are printed at the operator's console, thus:

???

Specific keys on the console are designated to assist the operator during command entry. These keys permit deletion of characters or command strings and halting of output being printed at the console.

All numbers entered or printed on the system console are decimal integers, except for I/O select codes specifying or reporting the location of the hardware peripherals. These I/O select codes are octal integers.

CHARACTER DELETION. If a typographical error is made while typing in a command, the under- score character (_) on the 2762A or the back arrow character (+-) on the 2754A/B performs as a delete key (sometimes called a backspace character). Press this key once for each previous character to be deleted. For example, the sequences:

ABC+-+-DE+-F (on the 2754A/B console), and ABC __ DE_F (on the 2762A console)

perform the same function and are both equivalent to the sequence ADF.

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COMMAND STRING DELETION. To delete an entire command string (prior to entry of the ter- minating carriage return) enter the control character XC (press and hold the CONTROL key, simultaneously press the X character key, then release both keys). When the system encounters this control character, the line being typed is ignored and a back slash character (\) is printed followed by a carriage retuf!l and a linefeed.

COMMAND PRINTOUT TERMINATION (BREAK REQUEST). The printing of output produced as a result of command entry can be terminated by pressing any key on the console. Printing then terminates at the end of the current line.

COMMAND DESCRIPTIONS

The system commands available to the operator are described on the following pages. Certain conventions are utilized in describing the system commands.

Command Description Conventions

In the following descriptions, the full commands are shown in uppercase characters. In the examples, only the required characters are shown. Parameters associated with the commands are shown in lowercase characters.

When required parameters are shown, a hyphen separates the parameter string from the command.

When parameters are optional, the parameter string is enclosed in brackets, [ ].

A parameter list enclosed in braces, { }, indicates the operator must choose one parameter from the list.

EXAMPLES:

The following parameters are required:

NEW-idcode, password, time limit, disc space The following parameter is optional:

DIR [-idcode]

In the following command, the first parameter is required; only one may be specified. The second parameter is optional:

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ANNOUNCE

The system operator may use the ANNOUNCE command to send a one-line message to a specific port or to all ports. The command is entered in the form:

{

port num her} .

ANNOUNCE- ALL ' character strzng

port number

ALL

character string

A decimal value from 0 to 31 designating a specific user port. If selected, the character string is transmitted to this port number.

If selected, the character string is transmitted to all ports.

A message of up to 66 characters including blanks. The message is transmitted to the port or ports specified by the first parameter.

The message is printed literally, including blanks, at the designated port or at all ports.

This command should be used with care because any output being printed at the user's terminal is interrupted with unexpected text. It is appropriate, however, to warn users shortly before system shutdown (see SLEEP and HIBERNATE commands).

Note: The message is not transmitted to a port that currently has the line printer assigned as its output device.

The user has a complementary command, MESSAGE with which to send a message to the operator.

EXAMPLES:

ANN-ALL,SYSTEM WILL BE SHUT DOWN IN 15 MINUTES.

warns user of approaching system shutdown.

ANN-10, YOUR REQUEST FOR MORE FILE SPACE IS GRANTED.

informs user at port 10 that his request for more file space has been granted.

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BESTOW

This command is used to transfer programs or files from the library of one user to that of another user. The command is entered in the following form:

BESTOW-ideode1 ,ideode₂[,name]

ideode 1 The identification code of the current owner of the program or file to be transferred.

ideode₂ The identification code of the destination owner of the program or file to be transferred.

name An optional parameter indicating the program or file name to be transferred from idcode ¹to idcode₂^• If omitted, the entire library of idcode 1 is transferred to the library of idcode₂•

Use of the BESTOW command results in the removal of one element or all elements in the library of the user designated by idcode₁and placement of the element or elements in the library of the user designated by idcode₂^• Elements in the library of idcode₁that duplicate names in the library of idcode₂are not removed or transferred.

A protected program or file transferred via the BESTOW command to another user's library loses its protected status following the transfer. A mask protected file retains its mask protected status following the transfer.

The BESTOW command should be used only when no users are logged on to the system because users cannot gain access to the system when this command is in execution, and any active files named in the BESTOW command will be transferred.

If the transfer of library elements cannot be completed, one of the following messages is printed:

NO ENTRIES FOR OLD ID NO SUCH NEW ID

LIBRARY SPACE FULL NO SUCH ENTRY INV ALID NAME DUPLICATE ENTRY DUPLICATE ENTRIES EXAMPLES:

BES-D123,B324

transfers the entire library of user ideode D123 to the library of user ideode B324.

BES-B444, C227,AAAAA

transfers a program or file named AAAAA from the library of user ideo de B444 to the library of

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BREAK

The BREAK command permits the operator to enable the BREAK capability at a specified port.

The command should be used only to override a BREAK capability disabled condition when the user's program is in an infinite loop during execution. The command is entered in the form:

BREAK-p~rt number

port number A decimal value from 0 to 31 designating the specific user terminal (port).

Entry of this command does not initiate a BREAK condition but enables the user to do so. The BREAK command remains in effect until the user's program has run to completion, the program terminates because of an execution error, the user terminates the program with the BREAK key, or until the user breaks the communication connection (hangs up or turns the terminal off).

If an illegal port number or more than one port number is specified, the message ILLEGAL FORMAT is printed. If the indicated port is not logged on, the message USER NOT LOGGED ON is printed.

EXAMPLE:

BRE-25

causes the BREAK capability disabled condition at port 25 to be overridden.

CHANGE

The system operator uses the CHANGE command tp modify any or all of the parameters of an existing user identification code. The command is entered in the form:

CHANGE-idcode,{password] ,{time limit] ,{disc space]

idcode

password

time limit

disc space

The identification code assigned to a specific user (see NEWID command).

If specified, this becomes the new password associated with the specified idcode.

If specified, this becomes the new terminal usage time limit (in minutes) associated with the specified idcode.

This value cannot exceed 65535.

If specified, this becomes the new disc space size limit associated with the specified idcode. This value cannot exceed 65535.

At least one parameter other than idcode should be specified. The parameters must be entered in the order shown and a comma must be entered as a place holder for any omitted parameter (trailing

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If the specified idcode does not exist or is not recognized by the system, the message NO SUCH ID is printed.

EXAMPLES:

CHA-Q123,BASIC

changes the password of user Q 123 to BASIC. The time limit and disc space limitations remain unchanged.

CHA -Q 123,,1000

changes the terminal time limit allotment of user Q 123 to 1000 minutes. The other parameters remain unchanged.

CHA-Q123",500

changes the disc space allotment of user Q 123 to 500 blocks. The other parameters remain unchanged.

ropy

This command is used to reproduce an element (program or file) from the library of one user within the library of another user. The command is entered in the form:

COPY-idcode 1 ,name 1 ,idcode₂,name 2

idcode!

name}

idcode₂

The identification code of the user in whose library the element to be copied resides.

The name of the element to be copied to another user.

The identification code of the destination user in whose library the element is to be copied.

The new name of the library element as it appears in the library of user idcode₂• This name can be the same as name 1 but cannot duplicate an existing name in the library of user idcode_{2 •}

The ownership of the library element is not transferred. The original owner retains the element identified by name! while the destination owner has a copy identified by name 2'

A protected program or file retains its protected status in the original library , but the copy in the new library is not protected. A mask protected file retains its mask protected status in the original

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users are logged on to the system because users cannot gain access to the system while this command is in execution.

If the copying function cannot be completed, one of the following messages is printed:

INV ALID NAME NO SUCH ENTRY

ILL-STORED PROGRAM LIBRAR Y SPACE FULL SYSTEM OVERLOAD DUPLICATE ENTRY UNSUCCESSFUL NO SUCH NEW ID

EXAMPLES:

COP-G4 76,ABC,M 935 ,DEF

produces a copy of an element named ABC from the library of user G476 in the library of user M935. The copy is named DEF.

COP-E722,lAMD,B079,lAMD

produces a copy of an element named lAMD from the library of user E 722 in the library of user B079. The copy has the same name as the original.

DESECRATE (options 002 and 003)

The DESECRATE command is used to return a sanctified program or file (see SANCTIFY command) from drum storage to the disc. This command is entered in the form:

DESECRATE-idcode,name idcode

name

The identification code assigned to a specific user (see NEWID command). This is the idcode of the user requesting the return of a sanctified program or file to the disc; it must be the same idcode as that used originally in the SANCTIFY command.

The name of the program or file to be returned to the disc.

Specification of both parameters is required. The program or file must have been previously sanctified and cannot be in use when the DESECRATE command is executed. The specified program or iile is returned to its original location .on the disc. The drum space it occupied is returned to the system.

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If execution of this command cannot be completed, one of the following messages is printed:

ENTRY NOT PRESENT ENTRY NOT SANCTIFIED

BAD TRANSFER, FILE DESTROYED FILE IN USE

EXAMPLE:

DES-H325,MYFIL

results in the return of a sanctified file named MYFIL from the drum to the disc library of user H325.

DIRECTORY

This command is available to the system operator and the System Master (user idcode AOOO) to ob- tain a printed list of library programs and files according to user idcode. Either a complete list or a partial list can be obtained. The command is entered in the following form:

DIRECTOR Y [-idcode]

idcode The identification code assigned to a specific user. If specified, the directory listing begins with this idcode and continues through the end of the directory entries.

If omitted, the listing includes all entries in the directory.

The directory listing is headed by the system identification and the current date and time. The idcodes are listed in the first column. The second column contains the library element names (program or file) associated with each idcode. The remaining columns contain information pertinent to each element, as follows:

Date and Element Type

Length

Disc

The data given is the date this element was last referenced (day-of-year/last two digits of year) followed by one or more of the characters C, F, P, or blank.

The character C indicates p. program in semi-compiled form. The character F appears if the element is a file.

The character P indicates a protected element. A blank indIcates that the element is a program in uncompiled form.

The element length in words (program) or in records (file). Length is given in decimal notation.

The disc location (logical block number, decimal) of the library element. .

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Drum The drum information column is printed under options 002 and 003 only. The drum location (drum-number/

track/sector) of sanctified elements (see DIRECTORY command).

If the command cannot be executed, the following message is printed:

CAN'T READ DIRECTORY TRACK EXAMPLE:

DIR

2000F 053/73 1443

ID

NAME DATE LENGTH DISC DRUM

AOOO

AAA

053/73 F 00002 000516

BUDGET 053/73 03431 000968

C 050/73 F 00031 000982

GT 042/73 F 00128 001512

XY 043/73 F 00256 001640

AlII ASTEST 042/73 00029 0018.96

FILE2 042/73 F 00012 001897

MYFILE 042/73 F 00012 001909

BIll APRIN 042/73 C 00024 003972

ASST 042/73 00043 003973

COM I 041/73 00016 003974

TAR 048/73 00595 003975

TARGET 048/73 C 00624 003978

B122 A 047/73 F 00003 003981 0/00/004

CHAR.F 047/73 F 00001 003984

CHAR.P 047/73 00032 003985

CHARX 047/73 00055 003986

FILCHK 048/73 00021 003987 0/00/003

FILFIL 048/73 00131 003988

TEST 042/73 00027 003989

Z999 HELLO 050/73 00320 004664

HSAV1 048/73 00128 004666

Note: The column labeled DRUM appears for options 002 and 003 only_ In this example, file A and program FILCHK under idcode B122 are sanctified and appear on both

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DISC

The DISC command can be used only during system loading. It is used to add moving-head discs to or remove them from the system. The format of the command follows:

DISC-disc number, select code, unit number disc number

select code

unit number

A value from 0 to 7 designating the logical disc number.

An octal value designating the lower-numbered select code of the controller to which the disc is connected.

A value indicating the disc's physical unit number on the controller.

System information and user libraries are stored on the moving-head discs. The system references information on the discs as a linear sequence of blocks; each block is 256 words in length (decimal).

The base system and option 001 require approximately 1250 blocks on a 16-port system and 2000 blocks on a 32-port system. Options 002 and 003 require approximately 500 blocks. The remainder of the disc space is for user programs and files. Included are the system library, group libraries and the private user libraries.

To remove a disc from the system, enter the command with a select code value of zero. In this case, the unit number parameter and preceding comma are not permitted.

Disc-O is assumed to be present by the loader; it can be neither moved nor removed from the system.

Under the base system and option 001, disc-O can be specified with a select code value of 15_{8 ;}under options 002 and 003, disc-O can be specified with a select code value of 178 . No other select code values are permitted for disc-O. This has no effect on disc-O.

The messages associated with system loading are given in Appendix A.

EXAMPLES:

DIS-1,21,2

adds disc-1 to the system. The disc is associated with the controller in I/O slot 21-228 and is unit 2 on the controller.

DIS-l,O

removes disc-1 from the system.

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DRUM (options 002 and 003 only)

The DRUM command can be used only during system loading. This command is used to add fixed-head drum storage to or remove it from the system. The command is entered in the form:

DRUM-drum number, select code drum number

select code

A value from 0 to 3 designating the logical drum number.

An octal value designating the lower-numbered select code of the controller to which the drum is connected.

The DRUM command informs the TSB system that a drum is added or removed. Drum-O is assumed present by the loader; it can be neither moved nor removed from the system. Thus, only the values 1 through 3 should be specified as the drum number parameter. Drum-O can be specified with a select code value of 148, This has the effect of unlocking any locked tracks on drum-O. No other select code is permitted for drum-O.

Whenever a drum is added to the system, all 64 tracks of the drum referenced in the DRUM command are unlocked even if the specified drum is already present on the system.

To remove a drum from the system, enter the command with a select code value of zero.

Up to 256 tracks of 128 sectors each are defined as drum storage in the TSB system. The tracks are allocated into four logical drums of 64 tracks each, numbered 0 through 3, regardless of the physical arrangement of the drum tracks. A drum unit having 128 tracks is defined as two logical drums of 64 tracks each, a 192-track drum as three logical drums. If the physical drum has fewer than 64 tracks or a number of tracks not evenly divisible by 64, any non-existing tracks must be locked using the LOCK command.

For example, a 48-track (physical) drum would be considered a 64-track (logical) drum with tracks 48. through 63 locked. A 96-track (physical) drum would be one full 64-track logical drum and a second logical drum of 64 tracks with tracks 32 through 63 locked.

Note: If this locking procedure is not followed during configuration of the system, the system will attempt to store information on nonexistent drum tracks.

When a drum has more than 64 logical tracks and is used as more than one logical drum, the order of entering DRUM commands determines the relation of drum numbers to tracks. Each DRUM command entered assigns the lowest available block of 64 tracks to the drum number specified in the command. For example, if the following commands are entered on a system where channels 14-158 contain a 128-track drum and channels 21-228 contain a 96-track drum:

DRU-l,14 DRU-2,21 DRU-3,21 LOC-3, 32,63

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Drum-O is assumed as tracks 0-63 of the first drum and DRU-1 refers to tracks 64-127 of the first drum. DRU-2 refers to tracks 0-63 of the second drum. DRU-3 refers to tracks 64-95 of the second drum. The LOCK command locks the remaining tracks (actually nonexistent) of the second drum.

DUMP

The DUMP command is a loader command. It can be entered by the operator only if the configuration options segment is selected during system updating or system start-up. At one point in the configuration options segment, the loader query "LOAD OR DUMP COMMANDS?" is printed.

The DUMP command may be entered at this time. It is not valid during normal operation of the TSB system.

DUMP command usage is described under "System Update" in Section IV.

HIBERNATE

This command is used to shut down the system while retaining a complete copy of the system and user libraries on magnetic tape. The command provides a systematic shut-down procedure that allows easy start-up at a later time. The format of the HIBERNATE command is:

HIBERNATE [-character string]

character string An optional message which, if specified, is sent to active users.

Entry of the HIBERNATE command results in the following actions:

a. If specified, a message is sent to the active users.

b. Active users are disconnected from the TSB system.

c. The current TSB system is copied onto disc storage.

Under options 002 and 003, sanctified programs and files are copied from drum storage back to their reserved positions on disc storage.

d. The entire TSB system is dumped onto magnetic tape for subsequent reloading. After writing each tape, the system prints the query VERIFY? Respond YES to rewind and compare the tape. If a tape verification fails, the system prints TAPE BAD and the main computer halts.

To try the dump again, use either the same tape or mount a new reel, then press RUN on the main computer. If more than one tape is required, the system calls for more tapes until the complete system is dumped. Additional tapes must not be mounted until requested. To by- pass verification, respond NO. Do not remove the tape reel until after the NO response is entered.

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e. After a successful system hibernation, the message DONE is printed and the main computer halts (the I/O processor does not halt). If another copy of the dump is desired, mount a new tape and press RUN on the main computer; the entire magnetic tape dump procedure is repeated.

f. The system may now be powered down.

It is appropriate that the ANNOUNCE command be used to warn active users of an impending system shut-down shortly before the HIBERNATE command is entered.

If the magnetic tape device select code was not defined prior to entry of the HIBERNATE command, the following error message is printed:

NO MAG TAPE

Enter the MAGTAPE command with the appropriate select code and enter the HIBERNATE command again.

EXAMPLES:

HIB

shuts down the TSB system with no communication to the active users.

HIB- GOOD BYE. TSB IS DOWN, WILL RETURN AT 0800 TOMORROW.

shuts down the TSB system with an informational message to the active users.

KILLID

The KILLID command allows the operator to remove a specified user from the TSB system. Com- mand format follows:

KILLID-idcode

idcode The identification code of the user to be removed from the system.

The specified user is completely removed from the system directory. Any disc files or programs assigned to the user are removed and the space is returned to the system. If the user is currently logged on at a terminal, he is immediately disconnected from the system. The System Master identification code (AOOO) may not be specified in this command. A Group Master identification code is not accepted if any member of his group is logged on when the KILLID command is entered. If a Group Master is removed from the system, his Group Library is also removed.

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Possible error messages resulting from entry of this command are:

AOOO NOT ALLOWED NO SUCH ID

GROUP LIBRARY IN USE

EXAMPLE:

KIL-Q123

removes the user assigned the identification code Q 123 from the system.

LOAD

This command is a loader command. It can be entered by the operator only if the configuration options segment is selected during system updating or system start-up. At one point in the configuration option segment, the loader query "LOAD OR DUMP COMMANDS?" is printed. The LOAD command may be entered at this time. It is not valid during normal operation of the TSB system.

LOAD command usage is described under "System Update" in Section IV.

LOCK (options 002 and 003 only)

The LOCK command allows the operator to make specific drum tracks unavailable to the TSB system. The command is entered in the form:

LOCK-n,track_l[, tra ck₂

1

n

track ¹

track 2

A single-digit integer, 0-3, representing the drum logical unit number.

Track number; 1 or 2 digits, 0-63; first or only track to be locked .

.

Optional track number; 1 or 2 digits, 0-63; last track to be locked in a range beginning at track}. If specified, track₂must be greater than or equal to track_l•

The LOCK command can be used to replace a drum in the TSB system by locking all tracks of the drum. When the new drum is installed, the tracks can be unlocked. (Adding a drum via the DRUM command automatically unlocks all 64 tracks.) The LOCK command is also used to eliminate physically faulty tracks.

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The first three sectors in track

°

of drum-O are reserved for the system bootstrap loaders; if this

tr~ck is referenced in a LOCK command (for example, LOC-O,O) all sectors of track 0 except the first three are made unavailable to the system.

Drums that do not have exactly 64 tracks can be used by locking those tracks that do not physically exist; that is, locking tracks 32-63 of the second logical drum of a 96-track physical drum.

When the system is reloaded from magnetic tape or disc, any tracks can be locked without loss of information.

If a LOCK command references an area containing sanctified user programs, the programs are returned automatically to disc storage (see the DESECRATE command). If a referenced area contains sanctified files, the files are destroyed and their associated disc space is returned to the system. If the area contains TSB system tables, the command is rejected because the system tables cannot be removed without destroying the system.

If the LOCK command cannot execute to completion, possible error messages are:

ILLEGAL PARAMETERS CAN'T LOCK TRACK tt NO SUCH DRUM

LOCK FEWER TRACKS

DISC/DRUM ERROR; CAN'T DO IT

EXAMPLES:

LOC-3,5 locks track 5 of drum-3.

LOC-3,5,7

locks tracks 5, 6, and 7 of drum-3.

MAGTAPE

The MAGTAPE command is used to inform the TSB system of the logical addition or removal of the magnetic tape unit. The command is entered in the form:

MAGTAPE-select code

select code An octal value indicating the I/O channel select code (high priority, lower number of the channel pair) of the magnetic tape unit; or, to remove the tape unit from the system, zero.

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Once the TSB system is informed of the presence of the tape unit via the MAGTAPE command, a copy of the system software is written to magnetic tape each time a HIBERNATE or SLEEP command is entered by the operator. This copy can be used to reload the system, if necessary. The magnetic tape unit must be present on the system to use the LOAD, DUMP, and HIBERNATE commands. Its presence is optional for the SLEEP command.

It is of prime importance to specify the correct select code with the MAGTAPE command (see

Hardware Configuration in Section II) because the system does not check this code before attempting to access the tape unit. If the wrong select code is specified, the system may become involved in an infinite loop. One indication of this type of error is the lack of activity on the tape unit.

To remove system access to the magnetic tape unit, enter the MAGTAPE command with a select code value of zero.

EXAMPLES:

MAG-21

informs the system that the magnetic tape unit is accessible on I/O channels 21-228- MAG-O

removes magnetic tape unit accessibility from the system.

MAG-17

informs the system that the magnetic tape unit is accessible on I/O channels _17-208,

MLOCK

The MLOCK command allows the operator to make specific disc blocks unavailable to the TSB system. MLOCK command format follows:

MLOCK-block} [, block21 block}

block2

Block number; must be greater than 3, maximum value depends on size of disc; first or only block to be locked.

Blo'ck number; must be greater than 3, maximum value depends on size of disc; last block to be locked in a range beginning at block}. If specified, block₂ must be greater than or equal to block} .

This command is used primarily to eliminate physically faulty areas on the disc.

When the TSB system is reloaded from magnetic tape or loaded from paper tape, any blocks can be locked without loss of information. However, at least 150 blocks on logical disc 0 must not be locked because portions of the system software must reside on this disc.